1. Field of the Invention
The present invention relates to a reproducing apparatus to perform a variable speed reproducing.
2. Description of Related Art
A reproducing apparatus such as a video cassette recorder (VCR), a digital versatile disc (DVD) recorder, or a hard disk recorder is adapted to enable a user to skip the part that the user does not want to hear or see, or to repeatedly hear and see a necessary part, during reproduction of reproduction data composed of sound data and/or image data by freely using a “fast-forward button,” a “rewind button,” and the like, provided in a remote controller (hereinafter referred to as a “remote control”).
However, for example, if the reproduction speed is shifted from a normal speed (1×-speed) to a 2×-speed by an instruction of a user and is fixed as it is, then the reproduction speed is changed from the normal speed to the 2×-speed in a moment. Consequently, human hearing processing cannot cope with the change, and the reproducing apparatus thus has a problem of the occurrence of failing to hear the necessary part.
Moreover, it is also known that, for example, if the time of high-speed reproduction such as 3×-speed reproduction is continued for 10 seconds or longer, the reproduced contents cannot be heard in almost all the cases, but that, if the continuation is made to be a short time for about 0.5 seconds, there is no failing to hear the contents in many cases.
The control of the reproduction speed of reproduction data to gradually change the reproduction speed dependently on the mechanical characteristics of a VCR and the control of the reproduction speed to stepwise increase/decrease the reproduction speed have been conventionally performed.
Moreover, the method of smoothly according an image with a sound was proposed (see, for example, Japanese Patent Application Laid-Open Publication No. 2001-103401). The method reproduces image data at a measurably increased speed, at a stepwise increased speed, or at a speed controlled by a spline function in order to reproduce the image data without causing any uncomfortable feelings when sound data is made to jump to a discontinuous position.
Moreover, the following two methods were proposed as the techniques of artificially changing a reproduction speed in order to make a change of the reproduction speed comfortable for a human being (see, for example, Japanese Patent Application Laid-Open Publications No. 2001-94948 and No. 2006-127647). The method disclosed in the JP-A No. 2001-94948 smoothly connects a reproduced part to the present broadcast by reducing the reproduction speed just before catching up with the present broadcast at the time of the follow-up reproduction (fast-forward reproduction up to the scene that is presently broadcasted). The method disclosed in the JP-A No. 2006-127647 divides a frame into the first half block and the second half block at the time of the high-speed reproduction of sound data to perform fade-out processing making the attenuation factor of the sound data gradually larger in the first half block, and to perform fade-in processing making the attenuation factor of the sound data gradually smaller in the second half block, and overlap the sound data of the first half block subjected to the fade-out processing with the sound data of the second half block subjected to the fade-in processing to smoothly connect the frames in the front and in the rear.
Now, the technique called as the time scale modification (TSM) of sound has been already publicly known as the technique of modifying the speech speed of a sound based on sound data so as to be easy for a user to hear (see, for example, Japanese Patent Application Laid-Open Publication No. Hei 10-257596). The use of the time scale modification technique enables the length of a sound to be changed without changing the height (pitch) of the sound.
Moreover, the method of determining a reproduction plan to make it easy to hear a sound on the premise of the time scale modification technique was proposed (see, for example, Japanese Patent Application Laid-Open Publication No. 2001-222300). The method disclosed in the JP-A 2001-222300 slowly reproduces a sound at the beginning of a document and rapidly reproduces the sound at the end of the document, and the reproduction plan of the method thereby makes it more easy to hear the sound in comparison with the case where the reproduction speed is the same at the beginning and at the end of a document even though the reproducing time is the same.
However, the aforesaid control of the reproduction speed of reproduction data to gradually change the reproduction speed dependently on the mechanical characteristics of a VCR and the control of the reproduction speed to stepwise increase/decrease the reproduction speed are only for moderating the degree of the disadvantages caused by a sudden change of the reproduction speed of reproduction data to the last, and are not the control able to optimally adjust the change of the reproduction speed of the reproduction data on the basis of human properties. Furthermore, the control methods cannot also optimally adjust the change of the reproduction speed of the reproduction data in consideration of the existence of an allowable range of the duration of high-speed reproduction.
Moreover, the JP-A No. 2001-103401 does not discloses the method of determining the optimal speed change, and the disclosed technique is only for moderating the degree of the disadvantage caused by a sudden change of the reproduction speed of reproduction data to the last. The technique cannot optimally adjust the change of the reproduction speed of the reproduction data on the basis of the human property.
Moreover, because the techniques disclosed in the JP-A No. 2001-94948 and No. 2006-127647 artificially change the reproduction speed, the techniques have a problem of causing an unnatural feeling for a human being. Furthermore, because the changes of the reproduction speeds by the techniques disclosed in the JP-A No. 2001-94948 and No. 2006-127647 are expedient and have no criterion of the optimality, they are also only for moderating the degree of the disadvantage caused by the sudden change of the reproduction speed of the reproduction data, and cannot optimally adjust the change of the reproduction speed of the reproduction data on the basis of the human property.
Moreover, the JP-A No. Hei 10-257596 discloses the technique for reproducing a clear sound on the basis of the determined reproduction plan (that is, the technique for reproducing a sound without generating noises), and does not discloses the technique to determine a reproduction plan for optimally adjusting the change of the reproduction speed of reproduction data on the basis of the human property.
Moreover, because the JP-A No. 2001-222300 does not describe the determination of the reproduction plan in the situation including fast-forward reproduction, the disclosure of the JP-A No. 2001-222300 does not enable the determination of the reproduction plan for optimally adjusting the change of the reproduction speed of reproduction data on the basis of the human property when a user instructs the fast-forward reproduction.